Heterosexuality

Abstract

Heterosexuality, which the Medical Subject Headings thesaurus classifies under sexuality, is the pattern of sexual or romantic attraction to the other sex. It is the statistically dominant orientation and the one a culture treats as its unmarked default, which is precisely why cognitive psychology finds it an instructive measurement problem: the baseline category is rarely examined as a thing in itself. This article reviews how heterosexuality is defined and located on a graded orientation scale, the sex difference in category-specific genital arousal that distinguishes heterosexual men from heterosexual women, what developmental and genetic evidence does and does not explain about its origins, and the finding that although exclusive heterosexual attraction is the most common and most stable pattern, it is neither perfectly fixed nor exempt from the fluidity seen across the spectrum.

Keywords: heterosexuality, sexual orientation, Kinsey scale, category-specific arousal, erotic plasticity

Introduction

Heterosexuality is the pattern of sexual or romantic attraction to the other sex (Bailey et al., 2016). As a form of sexual orientation it occupies one pole of the orientation spectrum and, as a matter of simple frequency, the great majority of any population sits at or very near it. That dominance is exactly what makes heterosexuality analytically peculiar: it is the category a culture treats as needing no explanation, the unmarked default against which every other orientation is defined and studied. Cognitive psychology resists that framing. It treats heterosexuality not as the absence of a question but as an orientation to be measured on the same graded instruments, with the same dissociable components, as any other.

Two features give heterosexuality its special status in orientation research. First, it is the modal anchor of the scale. On the Kinsey continuum the exclusively and near-exclusively heterosexual ratings hold the bulk of the distribution, so heterosexuality defines where the measure is densest and where its zero point is placed (Kinsey et al., 1948). Second, being the baseline makes it the reference against which differences are read: the sex difference in category-specific arousal, the plasticity of the female sex drive, and the genetics of orientation are all reported as departures from, or variations within, the heterosexual norm (Chivers et al., 2010; Baumeister, 2000).

The Medical Subject Headings thesaurus indexes Heterosexuality beneath Sexuality in its classification of behavior. That placement is a retrieval convenience, not a theoretical claim about kinds of people; this article uses it only to situate heterosexuality among related orientations and otherwise treats the psychology on its own terms, beginning with how the pattern is measured.

Measuring Heterosexuality

Heterosexuality became a measurable idea the moment orientation was treated as graded rather than categorical. Kinsey, Pomeroy, and Martin (1948) placed people on a seven-point continuum from exclusively heterosexual (0) to exclusively homosexual (6), and heterosexuality, in that scheme, is not a single point but the low region — ratings 0 and 1 — where most of the distribution lives. The scale made two things visible at once: that heterosexuality is overwhelmingly the modal orientation, and that it is nonetheless a region with internal gradation rather than an all-or-nothing state, since a rating of 1 records incidental other-pole response within a predominantly heterosexual pattern.

Being the densest part of the scale creates a measurement paradox. A category that almost everyone occupies is easy to count and hard to study, because the questions that sharpen a minority orientation — how is it recognized, how does it develop, how stable is it — are rarely asked of the default. Savin-Williams and Ream (2007) showed that the answer still depends on which component is measured: attraction, behavior, and identity do not pick out exactly the same people even at the heterosexual pole, because a small share report an attraction, a behavior, or an identity that departs from exclusive heterosexuality while the other components do not. The heterosexual majority is therefore slightly different in size depending on whether one counts who is attracted only to the other sex, who behaves that way, or who so identifies.

Whether orientation needs one dimension or two bears on the heterosexual pole as much as on the middle. Lippa (2020) analyzed interest, personality, and sexual traits across orientation groups and asked whether variation is better captured by one bipolar hetero–homosexual axis or by two partly independent dimensions — other-sex and same-sex attraction considered separately. On the two-dimensional view, heterosexuality is high other-sex attraction paired with low same-sex attraction, and that formulation matters because it treats the heterosexual pattern as a positive profile to be measured rather than as the mere absence of same-sex attraction. Figure 1 shows the shape of the distribution the scale records.

The first demonstration makes the distribution interactive, letting the reader switch between attraction, behavior, and identity and watch how the measured size of the heterosexual majority shifts with the component counted.

Arousal and the Sex Difference

The clearest window on heterosexual arousal is the construct of category-specificity: the degree to which genital arousal is selective for one sex. Chivers and colleagues (2010) meta-analyzed studies recording both self-reported and genital arousal and found a large, reliable sex difference. In men, genital response is strongly category-specific and agrees closely with self-reported attraction: a heterosexual man shows marked genital arousal to female stimuli and little to male stimuli, and his body and his report tell the same story. In women, including heterosexual women, genital response is far less category-specific — substantial arousal is recorded to stimuli of both sexes regardless of stated orientation, and genital and self-reported arousal agree much less well.

This difference reframes what “heterosexual arousal” even means, because it means something measurably different in the two sexes. Rieger, Chivers, and Bailey (2005), working on bisexual men, relied on exactly the male category-specificity that makes genital arousal a usable index of orientation in men; the same method applied to women would be far less diagnostic. For heterosexual men, then, the physiological measure and the self-report converge, and genital response can stand in for attraction. For heterosexual women, the two measures come apart, and a category-specific genital reading cannot be assumed to track the orientation a woman reports. The sex difference is not a flaw in the instrument but a finding about how heterosexual arousal is organized.

The consequence is methodological and it is large: a tool validated on heterosexual men does not transfer unchanged to heterosexual women. The second demonstration models the contrast directly, letting the reader switch the respondent's sex and watch category-specific genital arousal sharpen for men and flatten for women while self-reported heterosexual attraction stays high for both.

Origins and Development

Because heterosexuality is the default, its development is seldom posed as a question — but the theories offered for orientation in general apply to it in full. Bem (1996) proposed the exotic-becomes-erotic (EBE) developmental theory precisely as an account of the majority as well as the minority pattern: childhood temperament channels a child toward sex-typical or sex-atypical activities, which determine which peers feel familiar and which feel different, and the sex that was experienced as exotic in childhood becomes the object of erotic attraction later. The usual heterosexual outcome, on this account, is not assumed but derived — the common case where a child's preferences are sex-typical, making the other sex the exotic one. Whatever its empirical standing, EBE is notable for refusing to treat heterosexuality as needing no developmental explanation.

The biology tells the same even-handed story. Hamer and colleagues (1993) reported a linkage between DNA markers on the X chromosome and male sexual orientation, an early and much-debated result that framed orientation as partly heritable rather than wholly chosen or wholly environmental. Three decades later, Ganna and colleagues (2019) analyzed the genetics of same-sex sexual behavior at the scale of hundreds of thousands of genomes and found no single gene and no simple pattern: many variants each contribute a tiny amount, the genetic influences on same-sex behavior are spread across the genome, and — crucially — they do not partition people into discrete heterosexual and homosexual kinds. The genetic architecture is continuous, which means heterosexuality and its alternatives are the ends of a graded distribution of the same underlying influences rather than the presence or absence of a dedicated cause. The developmental and genetic pictures converge on one point: there is no special mechanism that produces heterosexuality, only the common settings of mechanisms that produce the whole range.

Prevalence, Stability, and Fluidity

How common heterosexuality is depends, as with any orientation, on what is counted — but at the heterosexual pole the components crowd close together. Savin-Williams and Ream (2007) found that exclusive heterosexual attraction, behavior, and identity are each the modal response, and that the great majority of adolescents and young adults are concordant across all three. The dissociation that makes the middle of the scale ambiguous is smallest here: most heterosexual people are heterosexual on every measure. Exclusive heterosexuality is also, on the same evidence, among the most stable patterns over time — the component disagreements and the year-to-year changes that appear elsewhere on the scale are least frequent at its densest point.

Stability, however, is not fixity, and the qualification is sharpest for women. Baumeister (2000) argued for erotic plasticity: the female sex drive is more responsive to social and situational circumstance than the male, which predicts that heterosexual attraction and identity are held somewhat more flexibly by women than by men. Diamond (2008) followed women over ten years and documented movement in both directions — some women moved away from exclusive heterosexual attraction and some moved toward it — while finding that heterosexual attraction was, on average, the most stable component in the sample. The two findings fit together: heterosexuality is the most stable orientation and still not immune to change.

That change is one instance of a general capacity. Mock and Eibach (2012) reported over a ten-year adult span that most people's identity was stable, with change concentrated among those not exclusively heterosexual, and Diamond (2016) argued that sexual fluidity — situation-dependent change layered on an underlying orientation — is a general human capacity rather than a female peculiarity. For the heterosexual majority this means the modal, most-stable orientation is still a point on a continuum that admits movement, not a fixed essence. The third demonstration makes the pattern visible, letting the reader watch how the stability of an orientation component falls as one moves from the exclusively heterosexual anchor toward the middle of the scale.

Worked Example

Consider one person assessed with the tools above: a woman who reports strong attraction to men, whose sexual history is entirely with men, who identifies as heterosexual, and who nonetheless shows, in a laboratory, substantial genital arousal to stimuli of both sexes. Is she heterosexual? On every component that defines orientation the answer is plainly yes — and the laboratory reading that seems to complicate it does not, once the sex difference is understood.

Attraction, behavior, and identity all place her at the exclusively heterosexual anchor, concordant across the three components, which is the modal and most stable configuration (Savin-Williams & Ream, 2007). Her genital arousal is not category-specific, but that is exactly what the evidence predicts for heterosexual women: female genital response is weakly selective for stimulus sex and agrees poorly with self-reported attraction, so a non-specific genital reading is uninformative about her orientation rather than evidence against it (Chivers et al., 2010). The same non-specific reading taken from a man would mean something quite different, because male genital response is category-specific. Table 1 lays the four measures side by side.

The example makes the article's point exact. The three components that define orientation agree, so she is heterosexual without qualification; the fourth measure disagrees only because it is the wrong index for her sex. A model that did not carry the sex difference in category-specificity would misread her non-specific arousal as ambiguity, when in fact it is the expected and uninformative signal of a measure that does not apply to women the way it applies to men (Rieger et al., 2005).

Discussion

The cognitive psychology of heterosexuality is, at its core, the discipline of refusing to let the majority orientation go unmeasured. Treated as the unmarked default, heterosexuality would be the thing every study presupposes and none examines; treated as an orientation, it is located on the same graded scale (Kinsey et al., 1948), described by the same positive two-dimensional profile (Lippa, 2020), and subjected to the same questions about arousal, development, and stability as any minority pattern.

Integrating the findings dissolves several apparent puzzles. The sex difference in category-specific arousal means heterosexual arousal is organized differently in men and women, so a genital measure that indexes orientation in men is uninformative in women rather than contradictory (Chivers et al., 2010; Rieger et al., 2005). The developmental and genetic evidence explains the heterosexual majority by the ordinary settings of general mechanisms, not by a dedicated cause, so there is no special story for the default any more than for the exceptions (Bem, 1996; Hamer et al., 1993; Ganna et al., 2019). And heterosexuality can be at once the most stable orientation and still mutable, because stability varies by component and by sex (Baumeister, 2000; Diamond, 2008; Mock & Eibach, 2012). The comprehensive review by Bailey and colleagues (2016) reaches the same integrative conclusion: orientation is real, early-emerging, and substantially stable across its range, and heterosexuality is the high-frequency region of that range rather than a separate kind of thing. As a monosexual pattern — attraction directed at a single sex — exclusive heterosexuality is measured on exactly the instruments that locate its exclusive-homosexual counterpart, the two differing in frequency and direction, not in the kind of measurement they require.

None of this reduces heterosexuality to any single measure. The point of the cognitive analysis is the opposite: by specifying which component is in view and how it is assessed, it explains why the default orientation, far from needing no study, repays exactly the measurement scrutiny the field has usually reserved for the exceptions.

Current Directions

The most consequential recent movement is the replacement of the categorical picture of orientation with a genuinely dimensional one, and heterosexuality is where that shift has the most to say. Ganna and colleagues (2019) established that the genetics of same-sex behavior are polygenic and continuous, with no variant that sorts people into discrete groups; the corollary, which the study makes explicit, is that there is no genetic boundary around heterosexuality either. The heterosexual majority is the dense end of a smooth distribution of many small influences, not a population defined by the absence of a gene. This reframes the oldest question about the default — what makes someone heterosexual — as the same question asked of everyone, answered by where they fall on a continuum rather than which box they are placed in.

That reframing turns the measurement themes of this article into an active research agenda. If orientation is dimensional (Lippa, 2020), then the heterosexual pole deserves the two-dimensional, component-specific measurement the middle of the scale forced on the field, rather than being scored as a residual. If erotic plasticity and fluidity are real and sex-differentiated (Baumeister, 2000; Diamond, 2016), then the stability of heterosexual attraction is a quantity to be estimated separately for women and men rather than assumed. And the robust sex difference in category-specific arousal (Chivers et al., 2010) leaves open a basic question the field is still pursuing: why heterosexual genital arousal is so sharply selective in men and so diffusely non-selective in women, and what that difference implies for every instrument built to measure orientation from the body.

Common Misconceptions

“Heterosexuality is the natural state and needs no explanation.”

Developmental and genetic theories of orientation apply to heterosexuality in full; the exotic-becomes-erotic account, for instance, derives the usual heterosexual outcome from the same mechanism it uses for minority orientations rather than assuming it (Bem, 1996).

“If someone shows arousal to both sexes in the lab, they cannot be heterosexual.”

In women, genital arousal is only weakly category-specific, so non-specific arousal is the expected reading for heterosexual women and is uninformative about orientation; the inference holds only for men, whose genital response is category-specific (Chivers et al., 2010).

“Heterosexual orientation is completely fixed and never changes.”

Exclusive heterosexual attraction is the most stable pattern on average, but a ten-year study found movement both toward and away from it, especially among women, consistent with erotic plasticity and general sexual fluidity (Diamond, 2008; Baumeister, 2000).

“A single gene or a single upbringing makes a person heterosexual.”

A genome-wide study of hundreds of thousands of people found orientation to be polygenic and continuous, with no single determinant and no genetic boundary separating heterosexual from other orientations (Ganna et al., 2019).

Glossary

Attraction.

The felt pull of sexual or romantic interest toward a sex; the component of orientation that defines heterosexuality and the one on which it is most clearly measured.

Category-specificity.

The degree to which genital arousal is selective for one sex; strong in heterosexual men, weak in heterosexual women, and the central sex difference in how heterosexual arousal is read.

Component (of orientation).

One of the separable aspects of orientation — attraction, arousal, fantasy, behavior, or identity — that are correlated but can give different answers for one person.

Concordance (of components).

The degree to which a person's separable orientation components agree; at the heterosexual pole concordance is high, the components mostly picking out the same people.

Erotic plasticity.

The responsiveness of the sex drive to social and situational circumstance; proposed to be greater in women than men, which predicts that heterosexual attraction is held somewhat more flexibly by women.

Exotic-becomes-erotic (EBE) theory.

Bem's developmental account in which childhood temperament determines which sex feels familiar and which exotic, and the exotic sex later becomes the object of attraction; it derives the heterosexual outcome rather than assuming it.

Heteroflexibility.

A predominantly heterosexual pattern of attraction or behavior that admits occasional same-sex response; the near-pole gradation a Kinsey rating of 1 records.

Heterosexuality.

The pattern of sexual or romantic attraction to the other sex; in cognitive psychology, the modal, low-end region of the orientation scale rather than the absence of same-sex attraction.

Kinsey scale.

A seven-point continuum from exclusively heterosexual (0) to exclusively homosexual (6); heterosexuality occupies its low region, ratings 0 and 1, which hold most of the distribution.

Monosexual.

Attracted to a single sex; exclusive heterosexuality is the high-frequency monosexual pattern, exclusive homosexuality the low-frequency one.

Prevalence.

The share of a population with a given orientation; for heterosexuality it is the majority on every component, though its exact size shifts slightly with whether attraction, behavior, or identity is counted.

Sexual fluidity.

Situation- and relationship-dependent change in attraction or identity layered on an underlying orientation; a general capacity that applies to heterosexuality despite its high stability.

Sexuality.

The multidimensional construct — attraction, arousal, fantasy, behavior, and identity — under which MeSH classifies heterosexuality and its sibling orientations.

Stability.

The tendency of an orientation component to persist across time; exclusive heterosexual attraction is, on longitudinal evidence, among the most stable, though not perfectly fixed.

Unmarked category.

A default against which others are defined and which is itself treated as needing no explanation; heterosexuality is the unmarked orientation, and cognitive psychology's move is to study it as if it were marked.

Key Researchers

J. Michael Bailey

is a professor of psychology at Northwestern University whose comprehensive review synthesized the measurement, development, and biology of sexual orientation across the heterosexual–homosexual range.

Faculty page - Google Scholar - Wikipedia

Roy F. Baumeister

is a social psychologist, professor emeritus at Florida State University and at the University of Queensland, whose concept of erotic plasticity holds that the female sex drive is more socially flexible than the male, predicting that heterosexual identity is held less rigidly by women.

ORCID - Google Scholar - Wikipedia

Daryl J. Bem

is a professor emeritus of psychology at Cornell University whose exotic-becomes-erotic theory offers a single developmental account of how both the majority heterosexual pattern and minority orientations arise from early temperament.

Faculty page - Wikipedia

Meredith L. Chivers

is a professor of psychology at Queen's University whose research established that genital arousal is strongly category-specific in heterosexual men but far less so in heterosexual women.

ORCID - Faculty page - Wikipedia

Lisa M. Diamond

is a distinguished professor of psychology and gender studies at the University of Utah whose decade-long longitudinal research showed that heterosexual attraction is on average the most stable orientation component yet still admits movement, especially among women.

Faculty page - Wikipedia

Alfred C. Kinsey

(1894–1956) founded the Institute for Sex Research at Indiana University and devised the graded scale of orientation on which exclusive heterosexuality occupies the low, modal region (ratings 0–1).

Wikipedia

Richard A. Lippa

is a professor emeritus of psychology at California State University, Fullerton whose analyses asked whether two independent dimensions, rather than a single hetero–homosexual axis, best represent variation in orientation, treating heterosexuality as a positive profile.

Faculty page

Ritch C. Savin-Williams

is a professor emeritus of developmental psychology at Cornell University whose research on the prevalence and stability of orientation components established that exclusive heterosexual attraction is the modal and most stable pattern.

ORCID - Faculty page - Google Scholar

Frequently Asked Questions

What is heterosexuality?

In research, heterosexuality is the pattern of sexual or romantic attraction to the other sex. Cognitive psychology treats it as the modal, low-end region of the orientation spectrum rather than as the natural absence of same-sex attraction, and studies it on the same graded instruments used for every other orientation (Bailey et al., 2016).

Where does heterosexuality fall on the Kinsey scale?

At the low end: ratings 0 (exclusively heterosexual) and 1 (predominantly heterosexual, with incidental other-pole response), which together hold the large majority of the distribution (Kinsey et al., 1948). Heterosexuality is a graded region of the scale, not a single point.

How common is heterosexuality?

It is the majority orientation on every component — attraction, behavior, and identity — and most heterosexual people are concordant across all three. The exact majority differs slightly depending on which component is counted, because a small share depart from exclusive heterosexuality on one measure but not the others (Savin-Williams & Ream, 2007).

Is heterosexual arousal the same in men and women?

No. Genital arousal is strongly category-specific in heterosexual men, tracking the sex they are attracted to, but only weakly category-specific in heterosexual women, who show substantial genital response to stimuli of both sexes regardless of stated orientation (Chivers et al., 2010). It is the central sex difference in how heterosexual arousal is measured.

What determines whether someone is heterosexual?

No single cause. Developmental accounts such as the exotic-becomes-erotic theory derive the heterosexual outcome from early temperament (Bem, 1996), and genome-wide evidence shows orientation to be polygenic and continuous, with no single gene and no genetic boundary around heterosexuality (Hamer et al., 1993; Ganna et al., 2019).

Is heterosexual orientation stable over time?

Exclusive heterosexual attraction is on average the most stable orientation component, and most heterosexual people's identity does not change (Savin-Williams & Ream, 2007; Mock & Eibach, 2012). Stable, however, is not the same as fixed.

Can heterosexual attraction change?

It can, especially in women. Erotic plasticity makes the female sex drive more responsive to circumstance (Baumeister, 2000), and a ten-year longitudinal study found movement both toward and away from exclusive heterosexual attraction, part of a general human capacity for sexual fluidity (Diamond, 2008; Diamond, 2016).

Why does cognitive psychology study heterosexuality at all, if it is the default?

Because treating it as the default that needs no study is itself a bias. Measuring the majority orientation on the same graded, component-specific, two-dimensional instruments used for minority orientations is what reveals its arousal sex difference, its developmental and genetic continuity with the rest of the scale, and the limits of its stability (Lippa, 2020).

References